Preheater for carburetor inlet air



April 24, 1962 J. '0. sARTO PREHEATER FOR CARBURETOR INLET AIR Filed June 26 1961 2 sheets-sheet 1 April 24, 1962 J. o. sARTo 3,030,943

PREHEATER FOR CARBURETOR INLET AIR Filed June 26, 1961 2 Sheets-Sheet 2 ,//7 I /f M y jid j /7/Z ,MZ

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ilnired States Patent G 3,030,943 PREHEATER FOR CARBURETOR INLET AIR Jorma 0. Sarto, Orchard Lake, Mich., assigner t Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Filed June 26, 1961, Ser. No. 119,569 6 Claims. (Cl. 12S- 122) This invention relates to preheating of the combustion supporting inlet air for an internal combustion engine `and has for an important object the provision of improved and simple means for rapidly preheating the inlet air and to achieve a substantially uniform inlet air temperature regardless of the ambient air temperature.

During cold and particularly during cool, damp weather below approximately 40 F. the fast idle cam of the conventional carburetor is effective to hold the throttle Valve at a partially open fast idle condition for a predetermined engine warmup period. Small/ice particles are thus enabled' to pass through the throttle valve without causing After the warmup period, the fast idle cam is no longer eifective to hold the throtttle open, so that icing becomes a serious problem during engine idling unless supplemental preheating of the `inlet air is provided. V

Various systems have been proposed heretofore for preheating the carburetor inlet air by means of the engine water coolant or the exhaust gases. Such systems, however, in order to operate effectively and with safety Vhave required thermostat controls and valving, especially to prevent overheating of cast aluminum engines Where exhaust gas preheating is employed. The additional expense and problems of servicing that arise from such systems have prevented their universal adoption. In addition, the use of the engine coolant water as customarily proposed has been unsatisfactory for preheating during the warmup stage because such water itself during cold weather is too cold for preheating purposes for several minutes after the fast idle cam becomes ineifective.

Another object of the invention is therefore to provide simple, improved and highly efficient means for utilizing the engine coolant water for carburetor air preheating, without recourse to auxiliary valving and temerature control means, and which enables sufficiently rapidly preheating of the inlet air so as to be effective to avoid icing Iand other cold weather problems by the time the customary carburetor fast idle cam becomes ineffective to hold the throttleV valve open during engine idling. p

t is customary in engine coolant systems to provide Van engine driven pump for circulating a liquid coolant such as water through a water jacet or cooling duct system in the Side walls of the engine. A thermostatically `actuated valve which is normally closed when the engine is cold controls the flow of coolant through an air cooled radiator arranged in series with the engine cooling duct system. in order to enable circulation of the coolant water when the valve is closed, a restricted controlled bythe thermostatically actuated valve as heretofore. Thus when the engine is operating below its The smaller re t optimum temperature and thermostatically actuated valve is closed, the coolant water in the engine cooling duct system circulates through the smaller radiator part. An air collector associated with the smaller radiator part discharges heated air therefrom to the customary carburetor air inlet system.

By virtue of this construction, the inlet air is brought into heat exchange relationship with the fluid coolant circulating through the bypass duct. Inasmuch as the mass of the fluid coolant circulating in the engine side walls by means of the bypass duct prior to opening of the thermostatically actuated valve to the radiator is comparatively small, this coolant in the engine side walls is heated rapidly and is effective for air preheating purposes before the customary fast idle cam becomes ineffective and appreciably before the thermostatically actuated radiator valve opens to connect the main body of coolant water in the larger radiator part with`the engine cooling duct system. Accordingly, during the time after the fast idle cam becomes ineffective and prior to the time that the main body of radiator water is heated sufii-y ciently for preheating the carburetor inlet air, the foregoing structure enables effective preheating to facilitate precise determination of the fuel-air mixture regardless of the ambient temperature and to prevent icing during cold or damp weather. The advantages derived from the present construction are accomplished by means of the customary thermostatically actuated flow control valve for the radiator, vso that supplementary temperature responsive means for the preheating system is unnecessary.

vOther objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

FIGURE 1 is a schematic side elevational view of an kautomobile engine embodying the present invention, portions being broken away to illustrate details of construction.

FIGURE 2 is a fragmentary front elevational View with portions broken away, taken in the direction of the arrows 2-2 of FIGURE l.

FIGURE 3 is a fragmentary sectional view taken in the direction of the arrows 3 3 of FIGURE 2.

FIGURE 4 is a view similar to FIGURE l, illustrating a modicaton.

FIGURE 5 is an enlarged elevational View with portions broken away, taken in the direction of the .arrows substantially along the line 5-5 of FIGURE 4.

It is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated Yin the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to the drawings, a particular embodiment of the present invention is illustrated by way of example with an internal combustion engine 1'0 having a water jacket for a water cooling duct system l1 in the side Walls of the engine for cooling the latter.- Any inlet l2 for the duct system 1l receives fluid coolant, such as water, from an engine driven pump 13 rotatable coaxially with a fan 14 driven by a conventional engine belt and pulley combination 15.

An outletl for the duct'system 11 is connected with the major portion 17 of an air cooledvradiator or heat exchanger by means of a hose IS-which discharges from the outlet 16 into an inlet header 19 for the'radiator part 17. Also in communication with the outlet 16 is a restricted port 20 connected by means of hose 21 with an inlet header 22 for a small or minor part 23 of the radiator. The radiator parts 17 and 23 comprise a plurality of small coolant ducts 24 and 25 respectively extending from their associated headers 19 and 22 to a common return header 26 connected by means of hose 27 to the return side or inlet of pump 13.

A thermostatic control valve 28 having its temperature responsive element 29 in communication with the coolant in outlet 16 normally closes the hose connection 18 when the coolant at outlet 16 is below a predetermined temperature. Above the predetermined temperature, the element 29 causes valve 28 to open to establish communication between outlet 16 and header 19 via hose 18.

Immediately rearward of the small radiator part 23 is an air collecting tray or scoop 30 arranged to provide a collecting chamber 31 for heated air. The chamber 31 discharges at 32 into duct 33 for discharging preheated combustion supporting air into the air inlet 34 of a carburetor 35. The latter may be of conventional construction and is mounted on engine in accordance with customary practice. Immediately in advance of the small radiator part 23 is an air filter 36 suitably secured in position, as for example by the wing nuts 37.

In accordance with the structure described, pump 13 circulates cooling water in the direction of the arrows through the cooling duct system 11 and thence into outlet 16. When valve 2S is closed, the small radiator part 23 provides a bypass to enable limited circulation of the fluid through duct system 11 by means of restriction 20, hose 21 and return hose 27. Also during operation, the fan 14 draws atmospheric air from front to rear through the radiator parts 17 and 23, whereby the radiator water circulating through these parts is cooled and the air passing therethrough is preheated. As indicated by the arrows in FIGURES l and 3, the air passing through small radiator part 23 is collected in chamber 31 and thence discharged as preheated air to the carburetor 35 via duct 33.

While the engine is operating during the warmup period prior to opening of valve 28, only a small portion of the total water or coolant in the radiator parts and duct system 11 will be circulating through the latter systemand radiator part 23. In consequence, this portion of coolant water will be warmed rapidly by the engine heat and will be effective to provide preheating of the atmospheric air flowing through the small radiator part 23. During the initial warmup period, the customary fast idle cam of the carburetor will be effective to maintain the usual carburetor` throttle valve cracked slightly open at a fast idle condition to assure idling and to minimize icing conditions'. As the engine warms to enable progressive opening of the customary thermostatically controlled carburetor choke valve, the fast idle cam becomes ineffective to maintain the throttle at a fast idle position. Shortly thereafter, the temperature of the coolant at outlet 16 increases sufficiently to cause opening of valve 28, thereby to enable circulation of the entire body of the coolant through the radiator parts 1.7 and 23 and cooling duct system 11. By virtue of the small radiator part 23 in the bypass circuit for the pump 13, the coolant circulating through the radiator portion 23 is effective for air preheating purposesl before the customary fast idle cam becomes ineffective and appreciably before the thermostatically actuated radiator valve 28 opens. Otherwise, a delay amounting to several minutes of engine idling or several miles of driving during cold weather would exist between the time of termination of the fast idle condition and the time of opening of valve 28 to enable use of the cooling water for air preheating in accordance with customary practice.

FIGURES 4 and 5 illustrate a modification of the present invention wherein in lieu of the hoses 18 and 21 and the arrangement of valve 28 illustrated in FIGURE l, a single hose 38 connects outlet 16 with an inlet chamber 39 for the radiator structure. Chamber 39 is connected by means of a restriction 20a with the inlet header 22a of a small radiator part 23a. The latter is similar in construction to the radiator part 23 and discharges into a return header 26a.

The chamber 39 also contains the thermostatic element 29 of valve 28 arranged in chamber 39 to control flow of coolant therefrom into inlet header' 19a for a large radiator part 17a, comparable to the radiator part 17 of FIGURE 1. The radiator part 17a discharges into header 26 which is connected by duct 26h with header 26a and which discharges through return hose 27 into the inlet of pump 13 as before. Also similarly to air scoop 30, scoop 30a is arranged immediately rearward of the small radiator part 23a to collect preheated air therefrom and to discharge the same via duct 33a into an air filter 36a, which may be of conventional construction and is suitably mounted on the air horn 34a of carburetor 35 to supply preheated combustion supporting air to the latter.

The operation and advantages of the structure illustrated in FIGURES 4 and 5 are substantially the same as described above in regard to the structure of FIGURES 1-3. In addition, a single hose 38 replaces the hoses 18 and 21. Also as illustrated in FIGURE 5, the thermostatic valve element 28, 29 is located immediately below the customary radiator refill cap 40. Thus installation and replacement of the thermostatic valve 28 is readily accomplished through the refill opening upon removal of cap 40.

In both modifications, the small radiator part 23 or 23a is designed to accommodate only a small portion of the total coolant flow when valve 28 is fully open. Satisfactory air preheating has been obtained wherein the fiow of coolant through the small radiator part is less than approximately one-third of the flow of coolant through the large radiator part. In a preferred construction with an automobile engine, adapted to operate under typical winter conditions at temperatures below approximately 15 'F., the small radiator part has been designed to conduct approximately fifteen percent of the total coolant flow when the engine is operating at its optimum temperature condition With valve 28 open.

I claim:

1. In combination with an automobile engine having a cooling duct system for uid coolant, a pump for said coolant, a two part heat exchanger for said coolant, conduit means connecting said pump, cooling duct system, and heat exchanger for circulating coolant through said cooling duct system and heat exchanger, thermostatic valve means in said conduit means responsive to the temperature of said coolant to restrict circulation thereof through one part of said heat exchanger when said temperature is less than a predetermined value and to open to enable circulation of said coolant freely through said one part when said temperature exceeds said predetermined value, flow restricting means in said conduit means for restricting the flow of said coolant through the other part of said heat exchanger, said heat exchanger being in heat exchange relation with the atmospheric air to heat thc same and cool said coolant, fuel charging means for said engine, and means for supplying heated combustion supporting air from said other part of said heat exchanger to said engine.

2. The combination according to claim l, the last named means comprising an air scoop arranged to collect heated air from said other heat exchanger part and being in communication with said fuel charging means to discharge said heated air thereto.

3. The combination according to claim l, said one heat exchanger part being adapted to cool the major portion of the coolant circulating through said cooling duct system when said valve means is open.

4. In combination with an automobile engine having a cooling duct system for fluid coolant, a pump for discharging said coolant into said cooling duct system, a heat exchanger in heat exchange relation with the atmospheric air and having a major part for cooling the major part of said coolant when said engine is operating at a predetermined temperature and also having a minor part for cooling a minor part of said coolant when said engine is operating at less than said predetermined temperature, conduit means connected with said cooling duct system to receive heated coolant therefrom and having separate portions in communication With said major and minor heat exchanger parts respectively to discharge heated coolant thereinto, said conduit means also connecting said heat exchanger parts with the inlet of said pump to return cooled coolant thereto, thermostatic valve means in the portion of said conduit means discharging into said major heat exchanger part to control the ow of coolant into the latter part and being responsive to the temperature of said coolant to restrict said llow when said temperature is less than a predetermined value and to open to enable circulation of said coolant freely through said major part when said temperature exceeds said predetermined value, means in said conduit means restricting the flow of said coolant through said minor heat exchanger part, fuel charging means for said engine, and means for supplying combustion supporting air from said minor heat exchanger part to said engine.

5. The combination according to claim 4, the two parts of said heat exchanger being arranged in juxtaposition Within a common supporting frame, a separate inlet header associated with each heat exchanger part respectively, Said heat exchanger having an inlet chamber, said conduit means including a single conduit connecting the outlet of said cooling duct system with said inlet chamber, said inlet chamber having a restricted outlet cornprising the means restricting the flow of said coolant through said minor heat exchanger part and being in communication With the inlet header for said minor heat exchanger part, said inlet chamber also containing the temperature responsive portion of said thermostatic valve means and being in communication via said valve means with the header for said major heat exchanger part, and

said conduit means also including a common coolant return duct connecting both heat exchanger parts with the inlet side of said pump to return coolant thereto.

6. In combination With an automobile engine having a cooling duct system for fluid coolant, a pump for discharging said coolant into said cooling duct system, a heat exchanger in heat exchange relation with the atmospheric air and having a major part for cooling the major part of said coolant when said engine is operating at a predetermined temperature and also having a minor part for cooling a minor part of said coolant when said engine is operating at less than said predetermined temperature, conduit means connected with said cooling duct system to receive heated coolant therefrom and having separate portions in communication with said major and minor heat exchanger parts respectively to discharge heated coolant thereinto, said conduit means also connecting said heat exchanger parts with the inlet of said pump to return cooled coolant thereto, thermostatic valve means in the portion of said conduit means discharging into said major heat exchanger part to control the flow of coolant into the latter part and being responsive to the temperature of said coolant to resrict said flow when said temperature is less than a predetermined value and to open to enable circulation of said coolant -freely through said major part when said temperature exceeds said predetermined value, means in said conduit means restricting the flow of said coolant through said minor heat exchanger part, fuel charging means for said engine, and means for supplying combustion supporting air from said minor heat exchanger part to said engine, the last named means comprising an air scoop arranged to collect heated air from said other heat exchanger part and being in communication with said fuel charging means to discharge said heated air thereto.

References Cited in the tile of this patent UNITED STATES PATENTS 1,639,032 Gross Aug. 16, 1927 2,058,204 Ball et al u- Oct. 26, 1936 2,369,937 Baster Feb. 20, 1945 2,989,956 Drinkard et al June 27, 1961 

